1. Event-related potentials reveal an early advantage for luminance contours in the processing of objects
- Author
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Alan Johnston, Marty Woldorff, Aurelio Bruno, Paul Hibbard, Pascal Mamassian, Frank Sengpiel, Sophie Wuerger, Bruno Richard, Jeroen J.A. Van Boxtel, Michael Webster, Eli Brenner, Pablo De Gracia, Jeroen Smeets, CHIEN-TE WU, Lucie Sawides, Sieu Khuu, Bruce Hansen, Almut Kelber, Jasna Martinovic, and Vebjørn Ekroll
- Subjects
Adult ,Male ,Visual perception ,genetic structures ,Light ,Computer science ,media_common.quotation_subject ,Color ,Stimulus (physiology) ,Electroencephalography ,Luminance ,Contrast Sensitivity ,Young Adult ,Optics ,Discrimination, Psychological ,Event-related potential ,Perception ,medicine ,Humans ,Computer vision ,Chromatic scale ,Evoked Potentials ,media_common ,Visual Cortex ,medicine.diagnostic_test ,business.industry ,Sensory Systems ,Form Perception ,Ophthalmology ,Sensory Thresholds ,Visual Perception ,Female ,Artificial intelligence ,Spatial frequency ,business ,Color Perception ,Photic Stimulation - Abstract
Detection and identification of objects are the most crucial goals of visual perception. We studied the role of luminance and chromatic information for object processing by comparing performance of familiar, meaningful object contours with those of novel, non-object contours. Comparisons were made between full-color and reduced-color object (or non-object) contours. Full-color stimuli contained both chromatic and luminance information, whereas luminance information was absent in the reduced-color stimuli. All stimuli were made equally salient by fixing them at multiples of discrimination threshold contrast. In a subsequent electroencephalographic experiment observers were asked to classify contours as objects or non-objects. An advantage in accuracy was found for full-color stimuli over the reduced-color stimuli but only if the contours depicted objects as opposed to non-objects. Event-related potentials revealed the neural correlate of this object-specific luminance advantage. The amplitude of the centro-occipital N1 component was modulated by stimulus class with the effect being driven by the presence of luminance information. We conclude that high-level discrimination processes in the cortex start relatively early and exhibit object-selective effects only in the presence of luminance information. This is consistent with the superiority of luminance in subserving object identification processes.
- Published
- 2011